A vehicle drive device is well known that includes a fluid transmission device having an input-side rotating element to which power from an engine is input and an output-side rotating element outputting power to drive wheels. For example, this corresponds to a vehicle drive device described in Patent Document 1. Such a vehicle drive device has an engine rotation speed (corresponding to a rotation speed of the input-side rotating element of the fluid transmission device) passively determined depending on a vehicle speed (corresponding to a rotation speed of the output-side rotating element of the fluid transmission device), the characteristic of the fluid transmission device, and the engine output. Power transmission efficiency is also passively determined in a mechanical path for fluid transmission of the engine output through the fluid transmission device.
If a temperature of operating oil (operating oil temperature) for actuating the fluid transmission device or an automatic transmission disposed on the subsequent stage of the fluid transmission device is lower, controllability may deteriorate in certain control in the fluid transmission device or the automatic transmission. Therefore, for example, it is contemplated that the certain control is not provided until warm-up completion when the operating oil temperature reaches a predetermined oil temperature or higher. However, the absence of implementation of the certain control may lead to deterioration in fuel efficiency performance or deterioration in power performance. Therefore, it is desirable to promote the warm-up of the fluid transmission device and the automatic transmission. For example, the warm-up of the fluid transmission device and the automatic transmission mainly depends on a heat loss due to a power transmission loss and, if an operating point is determined, the warm-up requires a certain time corresponding to the operating point. In a technique proposed in Patent Document 1, an electric motor is included for a stator impeller of a torque converter and if an operating oil temperature is equal to or less than a predetermined value, the stator impeller is rotationally driven by the electric motor to reduce a capacity coefficient of the torque converter and make a loss of the torque converter larger, thereby promoting the warm-up.